本文主要介紹了node使用Koa2建造web專案的方法,小編覺得挺不錯的,現在分享給大家,也給大家做個參考。一起跟著小編過來看看吧,希望能幫助大家。
隨著Node.js的日益火熱,各種框架開始層出不窮的湧現出來,Node.js也開始逐漸的被應用到處理服務端請求的場景中。搭建Web專案的框架也隨之開始出現──express、koa、koa2、egg等,當然要了解其好壞還是要自己去啃原始碼的。本文將不會涉及原始碼,只是帶領初學者簡單了解下Koa2的基本使用,歡迎大家在評論中互相交流學習。
注意:koa2使用了ES7的語法,所以使用時請升級Node版本到最新。了解更詳細的原始碼資訊可以到git上的koajs/koa去了解
1.專案目錄結構
##2. 程式碼邏輯解析
2.1. 套件結構檔
[package.json]{ "name": "weixin-node-koa", "version": "1.0.0", "description": "node.js with koa2", "private": true, "dependencies": { "koa": "^2.0.0", "koa-router": "^7.0.0", "mysql":"2.13.0" }, "scripts": { "start": "node app.js" }, "engines": { "node": ">=6.0.0" }, "author": "Fly", "license": "CENTERM" }
2.2. 啟動入口檔案
[app.js]const Koa = require('koa'); const app = new Koa(); const router2controller = require('./app/router2controller.js'); const config = require('./config/config.local.js'); app.use(router2controller()); app.listen(config.port); console.log("Server started and listen on port " + config.port);
const Koa = require('koa'); const app = new Koa(); const router2controller = require('./app/router2controller.js'); const config = require('./config/config.local.js'); //start接收到的xml数据请求单独解析存储 const xmlParser = require('koa-xml-body'); app.use(xmlParser()).use((ctx,next) => { ctx.data = ctx.request.body; return next(); }); //end app.use(router2controller()); app.listen(config.port); console.log("Server started and listen on port " + config.port);
2.3. 路由器文件
[router2controller.js]#此類將會自動掃描controller資料夾中的檔案來載入請求映射,不需要挨個請求單獨配置router .get('/', async (ctx,next) => { this.body = 'Hello World!'; }) .post('/users', async (ctx,next) => { //TODO }) .put('/users/:id', async (ctx,next) => { //TODO }) .del('/users/:id', async (ctx,next) => { //TODO });
#
const fs = require('fs'); const router = require('koa-router')(); function addMapping(router, mapping) { for (var url in mapping) { if (url.startsWith('GET ')) { var path = url.substring(4); router.get(path, mapping[url]); console.log(`register URL mapping: GET ${path}`); } else if (url.startsWith('POST ')) { var path = url.substring(5); router.post(path, mapping[url]); console.log(`register URL mapping: POST ${path}`); } else if (url.startsWith('PUT ')) { var path = url.substring(4); router.put(path, mapping[url]); console.log(`register URL mapping: PUT ${path}`); } else if (url.startsWith('DELETE ')) { var path = url.substring(7); router.del(path, mapping[url]); console.log(`register URL mapping: DELETE ${path}`); } else { console.log(`invalid URL: ${url}`); } } } function addControllers(router, dir) { fs.readdirSync(__dirname + '/' + dir).filter((f) => { return f.endsWith('.js'); }).forEach((f) => { console.log(`process controller: ${f}...`); let mapping = require(__dirname + '/' + dir + '/' + f); addMapping(router, mapping); }); } module.exports = function (dir) { var controllersDir = dir || 'controller'; addControllers(router, controllersDir); return router.routes(); };
2.4.控制器
***Controller.js是用來處理具體請求資訊以及返回資料的,userController.js中處理了GET請求獲取使用者資訊,POST請求保存使用者資訊
const userService = require('./../service/userService.js'); var getUserinfo = (ctx, next) => { let query = ctx.query; let userId = query.id; let userInfo = userService.getUserById(userId); let html = '<html><body>' + '<p> userinfo: ' + userInfo + '</p>' + '</body></html>'; ctx.response.type ='text/html'; ctx.response.body = html; }; var saveUserinfo = (ctx, next) => { const requestString = ctx.data; //TODO数据处理 Console.log(requestString); }; module.exports = { 'GET /getUserinfo': getUserinfo, 'POST /saveUserinfo': saveUserinfo };
處理封裝從***Dao .js取得到的資料回傳至Controller
const userDao = require('./../dao/userDao.js'); var getUserById = async (userId) => { var users = userDao.getUserById(userId); var responseContent = ''; for(let user of users) { reaponseContent += '姓名:' + user.name + ' |'; reaponseContent += '年龄:' + user.age + ' |'; reaponseContent += '身高:' + user.height + '<br />'; } return responseContent; } module.exports = { getUserById : getUserById };
透過請求傳入參數來取得user資料
const mysql = require('./../utils/mysqlUtil.js'); var getUserById = async (userId) => { let mysqlOptions = { sql : 'select * from table_user where user_id = ?', args : [userId] }; var users = await mysql.execQuery(mysqlOptions); if(users.length == 0) { return null; } else { return users; } }; module.exports = { getUserById : getUserById };
[ mysqlUtil.js]包含了資料庫連線池控制,連線建立、釋放管理,執行Dao發起的資料庫操作請求
###########const mysql = require('mysql'); const config = require('./../../config/config.local.js'); var connectionPool = mysql.createPool({ 'host' : config.database.host, 'port':config.database.port, 'user' : config.database.user, 'password' : config.database.password, 'database' : config.database.database, 'charset': config.database.charset, 'connectionLimit': config.database.connectionLimit, 'supportBigNumbers': true, 'bigNumberStrings': true }); var release = connection => { connection.end(function(error) { if(error) { console.log('Connection closed failed.'); } else { console.log('Connection closed succeeded.'); } }); }; var execQuery = sqlOptions => { var results = new Promise((resolve, reject) => { connectionPool.getConnection((error,connection) => { if(error) { console.log("Get connection from mysql pool failed !"); throw error; } var sql = sqlOptions['sql']; var args = sqlOptions['args']; if(!args) { var query = connection.query(sql, (error, results) => { if(error) { console.log('Execute query error !'); throw error; } resolve(results); }); } else { var query = connection.query(sql, args, function(error, results) { if(error) { console.log('Execute query error !'); throw error; } resolve(results); }); } connection.release(function(error) { if(error) { console.log('Mysql connection close failed !'); throw error; } }); }); }).then(function (chunk) { return chunk; }); return results; }; module.exports = { release : release, execQuery : execQuery }
以上是node使用Koa2搭建web項目的詳細內容。更多資訊請關注PHP中文網其他相關文章!